1/* Memory allocation on the stack.
2   Copyright (C) 1995, 1999, 2001-2005 Free Software Foundation, Inc.
3
4   This program is free software; you can redistribute it and/or modify it
5   under the terms of the GNU General Public License as published
6   by the Free Software Foundation; either version 2, or (at your option)
7   any later version.
8
9   This program is distributed in the hope that it will be useful,
10   but WITHOUT ANY WARRANTY; without even the implied warranty of
11   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
12   General Public License for more details.
13
14   You should have received a copy of the GNU General Public
15   License along with this program; if not, write to the Free Software
16   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
17   USA.  */
18
19/* When this file is included, it may be preceded only by preprocessor
20   declarations.  Thanks to AIX.  Therefore we include it right after
21   "config.h", not later.  */
22
23/* Avoid using the symbol _ALLOCA_H here, as Bison assumes _ALLOCA_H
24   means there is a real alloca function.  */
25#ifndef _GNULIB_ALLOCA_H
26#define _GNULIB_ALLOCA_H
27
28/* alloca(N) returns a pointer (void* or char*) to N bytes of memory
29   allocated on the stack, and which will last until the function returns.
30   Use of alloca should be avoided:
31     - inside arguments of function calls - undefined behaviour,
32     - in inline functions - the allocation may actually last until the
33       calling function returns,
34     - for huge N (say, N >= 65536) - you never know how large (or small)
35       the stack is, and when the stack cannot fulfill the memory allocation
36       request, the program just crashes.
37 */
38
39#ifdef __GNUC__
40# ifndef alloca
41#  define alloca __builtin_alloca
42# endif
43#else
44# ifdef _MSC_VER
45#  include <malloc.h>
46#  define alloca _alloca
47# else
48#  if HAVE_ALLOCA_H
49#   include <alloca.h>
50#  else
51#   ifdef _AIX
52 #pragma alloca
53#   else
54#    ifdef __hpux /* This section must match that of bison generated files. */
55#     ifdef __cplusplus
56extern "C" void *alloca (unsigned int);
57#     else /* not __cplusplus */
58extern void *alloca ();
59#     endif /* not __cplusplus */
60#    else /* not __hpux */
61#     ifndef alloca
62extern char *alloca ();
63#     endif
64#    endif /* __hpux */
65#   endif
66#  endif
67# endif
68#endif
69
70#endif /* _GNULIB_ALLOCA_H */
71